Insecticidal phenols

ABSTRACT

2,6-Di-(branched alkyl)-4-(halovinylthio) phenol compounds of the formula   WHEREIN R1 and R2 are branched alkyl groups of 3 to 6 carbon atoms and X individually is hydrogen, fluorine, chlorine, bromine or iodine, with the proviso that at least one X is halogen, have morphogenetic hormonal mimetic activity on mosquitos.

United States Patent [191 Moore et a].

[ 1 Feb. 18, 1975 INSECTICIDAL PHENOLS [75] Inventors: Joseph E. Moore, Richmond;

Gustave K. Kohn, Berkeley, both of Calif.

[73] Assignee: Chevron Research Company, San

Francisco, Calif.

[22] Filed: Oct. 3, 1973 21 Appl. N07: 403,300

Related US. Application Data [63] Continuation-impart of Ser. No. 300,082, Oct. 24,

1972, Pat. No. 3,793,274.

OTHER PUBLICATIONS Chem. Abst. 75, 983176 (I971).

Chem. & Eng. News, 11/29/71, pp. 9-10.

Borkovec, Insect Chemosterilants, pp. 61-63, 1966.

Primary Examiner-Jerome D. Goldberg Assistant Examiner-Allen J. Robinson Attorney, Agent, or FirmG. F. Magdeburger; Jr. Stoner; Raymond Owyang 57 ABSTRACT 2,6-Di-(branched alkyl)-4-(halovinylthio) compounds of the formula phenol no scx=cx wherein R and R are branched alkyl groups of 3 to 6 carbon atoms and X individually is hydrogen, fluorine, chlorine, bromine or iodine, with the proviso that at least one X is halogen, have morphogenetic hormonal mimetic activity on mosquitos.

8 Claims, No Drawings INSECTICIDAL PHENOLS RELATED APPLICATION This application is a continuation-in-part of application Ser. No. 300,082, filed Oct. 24, 1972, now U.S. Pat. No. 3,798,274 the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is concerned with insecticidal compounds which have morphogenetic hormonal mimetic activity. Compounds having morphogenetic hormonal mimetic activity exert a disrupting influence upon the normal development of insects. These compounds interfere with the normal metamorphosis of the pest insects and result in the formation of individual insects of the treated species which develop abnormally and are nonviable or sterile. This ultimately leads, indirectly at least, to the destruction of the insect population.

2. Description of the Prior Art Chemical and Engineering News, Nov. 29, 1971, pages 9l(). discloses the use of 2.6-di-t-butyl-4(a,adimcthylbenzyl) phenol as a mosquito larvicide.

Japanese Pat. No. 16,970, issued May 11, 1971 (Chem. Abs. 75, 983l7e [1971] discloses the use of 2,6-di-t-butyl-4-phenylthiophenol as an insecticide. U.K. Pat. No. 1,311,577 (Belgian Pat. No. 767,834) discloses the use of 2,6-di-t-butyl-4-alkylthiophenols for the control of mosquitos. U.I(. Pat. No. 1,313,597 discloses a process for preparing 4-arylthio-2,6- dialkylphenols.

SUMMARY OF THE INVENTION It has now been found that 2,6-di-(branched aIkyl)-4- halovinylphenols are effective for the control of mosquitos when applied in insecticidally effective amounts to pre-adult mosquitos.

DESCRIPTION OF THE INVENTION The phenols of the invention are represented by the formula (I) no sex-ex:

wherein R and R are branched alkyl groups of 3 to 6 carbon atoms attached to the aromatic ring through a secondary or tertiary carbon atom and X is individually hydrogen, fluorine, chlorine, bromine, or iodine, with the proviso that at least one X is a halogen. Preferably X is chlorine or bromine.

Representative branched alkyl groups which R and R may represent include s-propyl, s-butyl, t-butyl, tamyl, s-hexyl, etc. R and R may be the same or different branched alkyl groups. Preferred R and R groups are attached to the aromatic ring through a secondary carbon atom (i.e., a carbon atom substituted with two alkyl groups) or a tertiary carbon atom (i.e., a carbon atom substituted with three alkyl groups).

Representative phenols of formula I include: 2,6-di-t-butyl-4-( l-chlorovinylthio) phenol. 2,6-di-t-butyl-4-(2-chlorovinylthio) phenol. 2,6-di-t-butyl-4-(2,2-dichlorovinylthio) phenol. 2,6-di-t-butyl-4-( 1,2-dichlorovinylthio) phenol. 2,6-di-t-amyl-4-(trichlorovinylthio) phenol, 2,6-di-sec-butyl-4-(trichlorovinylthio) phenol. 2,6-diisopropyl-4-( l-bromovinylthio) phenol. 2,6-di-t-amy1-4-(Z-bromovinylthio) phenol. 2,6-di-sec-hexyl-4-( 1.Z-dibromovinylthio) phenol. 2,6-di-t-butyI-4-(lldibromovinylthio) phenol, 2,6-diisopropyl-4-(tribromovinylthio) phenol. 2-t-butyl-6-t-amyl-4-( l-chloro-2-bromovinylthio) phenol, 2-t-butyl-6-t-butyI-4-( l-chloro-2,2-

dibromovinylthio) phenol, 2-t-butyl-6-t-butyl-4-( l-bromo-2,2-

dichlorovinylthio) phenol, 2,6-di-t-butyl-4-( l-fluorovinylthio) phenol, 2,6-di-t-butyl-4-( I-iodovinylthio) phenol, 2,6-di-t-butyl-4-(2-fluorovinylthio) phenol, 2,6-di-t-butyl-4-(2,2-difluorovinylthio) phenol, 2,6-di-t-butyl-4-( l-chloro-2,2-difluorovinylthio) phenol, 2,6-di-t-butyl-4-(1-iodo-2,Z-dichlorovinylthio) phenol, 2,6-di-t-butyl-4-( l-fluoro-2,2-dichlorovinylthio) phenol, 2,6-di-t-butyl-4-( 1.2-difluorovinylthio) phenol. 2,6-di-t-butyl-4-(trifluorovinylthio) phenol. 2,6-di-t-butyl-4-( l-bromo-2.Z-difluorovinylthio) phenol, and 2,6-di-t-butyl-4-( l-fluoro-2,Z-dibromovinylthio) phenol. The phenols of formula I are prepared by the reaction of a 2,6-di(branched alkyl) phenol and a halovinylsulfenyl chloride as depicted in the following equation cx-cx s -m (II) (III) no s-cx-cx acl wherein R, R and X have the same significance as 6&

fined in formula I.

The reaction depicted in equation 1 is conducted by more or less conventional procedures. The molar ratio of the phenol (II) to the sulfenyl halide (III) is substantially equimolar. The reaction is conducted in a solvent such as acetic acid. Reaction temperatures suitably vary from 0 to C. The product is isolated by conventional methods such as extraction, distillation, crystallization, etc.

The compounds of the invention are useful as morphogenetic hormonal mimetic insecticides, particularly against mosquitos such as Aedes aegypti, Culex pipiens quinque fasciatus and Culiseta inornata.

The compounds are very potent and are used at extremely low concentrations. For example, compositions containing 100 to 0.01 ppm, preferably from 5 to 0.1 ppm, are effective for the control of insects. However, the effective concentration depends in part on the mode of application and the particular insect.

The compounds may be applied in either liquid or solid formulations to the pre-adult insects or their environment. For example, they may be sprayed or otherwise applied directly to plants or aqueous bodies so as to effect control of insects coming into contact therewith.

Formulations of the compounds of this invention will comprise a toxic amount of one or more of the compounds and a biologically inert carrier. Usually they will also contain a wetting agent. Solid carriers such as clay, talc, sawdust, alfalfa meal. and the like may be used in such formulations. Liquid diluents which may be used with these compounds include water and aromatic solvents. In addition, these formulations may contain other compatible pesticides, fillers, stabilizers, attractants and the like.

The concentration of the active ingredient to be used with inert carriers, either solid or liquid carriers, will be dependent upon many factors, such as the particular compound which is used, the carrier in or upon which it is incorporated, the method and conditions of application, the insect species to be controlled, etc., the proper consideration of these factors being within the skill of those versed in the art. In general, the toxic ingredients of this invention will be effective in concentrations from about 0.0001 percent by weight to as high as 50 percent by weight or higher. Economically, of

course, it is desirable to use lower concentrations of this active ingredient. Thus, it is usually desirable to use less than 20 percent by weight of the active ingredient in a particular composition.

The compounds of the invention are particularly useful in combination with mosquito larvicidal petroleum oil dispersions. Petroleum oils suitable as mosquito larvicidal dispersions are known. Such hydrocarbon oils include mineral oils such as naphthenic base and paraffinic base lubricating oils, etc., as well as synthetic oils. Such hydrocarbon oils are nonphytotoxic and generally contain not more than a few percent aromatics. Particularly suitable hydrocarbon oils have boiling points above 350 to 400F. and viscosities of from about 33 to 200 SSU at 100F.

The amount of the compound of the invention employed in petroleum oil generally ranges from 0.1 to percent by weight based on weight of oil. The hydrocarbon oil dispersions containing the compounds of the invention are contacted with or applied to the surface of the aqueous bodies wherein mosquito control is desired by conventional methods.

The terms "insecticide" and insect as used herein refer to their broad and commonly understood usage rather than to those creatures which in the strict biological sense are classified as insects. Thus, the term insect is used not only to include small invertebrate animals belonging to the class lnsccta but also to other related classes of arthropods whose members are segmented invertebrates having more or fewer than six legs, such as spiders, mites, ticks. centipedes. worms and the like.

EXAMPLE 1 1l0C./O.3 mm of Hg). The pot residue solidified on cooling. The residue was chromatographed on silica gel (hexane eluant) to give the crude product as a yellow solid. Recrystallization from hexane gave product which melted at 74-76C; Elemental analysis showed: %Cl, calculated 28.9, found 28.6; %S, calculated 8.7,

found 8.9. Y V

EXAMPLE 2 Preparation of 2,6-di-sec.-butyl-4-(trichlorovinylthio) phenol By a procedure similar to that of Example 1, 2,6-disec.-butyl-4-trichlorovinylthio) phenol was prepared from 2,6-di-sec.-butylphenol and trichlorovinylsulfenyl chloride. The product was obtained as a yellow oil after chromatography on silica gel and had the following elemental analysis: %Cl, calculated 28.9, found 28.8; 7(S, calculated 8.7, found 8.6.

EXAMPLE 3 2,6-Di-t-butyl-4-(trichlorovinylthio) phenol (Compound A) was tested as a morphogenetic hormonal mimetic insecticide against Yellow Fever mosquito larvae (Aedes aegypli) by the following procedure: Late fourth-stage larvae of the mosquito are placed in a cup containing 200 ml. of deionized water containing a known amount of the phenol compound dissolved therein. About 20 larvae are used per test. The larvae are fed and allowed to pupate. The live pupae are kept until the adult emerges. A count is made at each step for mortality, i.e., larvae, pupae and adult mortality.

For comparison, 2,6-di-t-butyl-4-(a,a-dimethylbenzyl) phenol (Compound B) was also tested. The concentration and the mortality counts are tabulated in Table I.

TABLE I Cone. Mortality Compound ppm Larvae Pupae Adults Total A 0.07 0 92.5 o 92.5 A 0.05 0 60 0 60 A 0.03 0 40 0 40 A 0.02 0 l5 0 15 A 0.0l 0 5 0 5 B 0.07 0 5 0 5 B 0.05 0 0 0 O B 0.03 0 0 0 0 B 0.02 0 0 0 (1 B 0.0l 0 0 0 0 2,6-Di-t-butyl-4-(trichlorovinyl) phenol was tested for the control of Aedes aegypti larvae by a procedure similar to that above, except that the phenol/water so- EXAMPLE 4 Petroleum Oil Formulation A 1 percent by weight formulation of 2,6-di-t-butyl- 4-(trichlorovinylthio) phenol was prepared with an oil composition having 96.1 percent by weight of a petroleum oil having an aromatic content of 8.4 percent by weight and a viscosity of 36.3 SSU at 100F, 0.9 percent by weight of ethoxylated dodecyl phenol (molecular weight 526 and 6 mols ethylene oxide per mol phenol) and 3 percent by weight of polyisobutenyl succinic anhydride (molecular weight 950).

The oil formulation was tested for the control of Acdcs uegypli larvae by applying a thin film of the oil formulation to a container containing larvae and I70 ml. ofwater. The larvae are fed and allowed to pupatc. After 2 days. a count is made of larva and pupa mortality. At a dosage corresponding to 0.33 gallon- /acre, the larva mortality was zero and the pupa mortality was 95 percent.

EXAMPLE 5 2.6-Di-sec.-butyl-4-(trichlorovinylthio) phenol was tested as a morphogenetic hormonal mimetic insecticide against Yellow Fever mosquito larvae by a procedure identical to that of Example 3. At a concentration of 1.7 ppm. the percent pupa mortality was 5 percent.

What is claimed is:

l. A method for killing mosquitos which comprises contacting pre-adult mosquitos with a metamorphosisinhibiting amount of a compound of the formula wherein R and R are branched alkyl of 3 to 6 carbon atoms attached to the aromatic ring through a secondary or tertiary carbon atom and X individually is chlorine or bromine, admixed with a biologically inert carrier.

6. A composition as in claim 5 wherein R and R are tertiary alkyl.

7. A composition as in claim 6 wherein X is chlorine.

8. A composition as in claim 7 wherein the compound is 2,6-di-t-butyl-4-(trichlorovinylthio) phenol. 

1. A METHOD FOR KILLING MOSQUITOS WHICH COMPRISES CONTACTING PRE-ADULT MOSQUITOS WITH A METAMORPHOSIS-INHIBITING AMOUNT OF A COMPOUND OF THE FORMULA
 2. The method of claim 1 wherein R1 and R2 are tertiary alkyl.
 3. The method of claim 2 wherein X is chlorine.
 4. The method of claim 1 wherein the compound is 2,6-di-t-butyl-4-(trichlorovinylthio) phenol.
 5. A composition comprising a metamorphosis-inhibiting amount of a compound of the formula
 6. A composition as in claim 5 wherein R1 and R2 are tertiary alkyl.
 7. A composition as in claim 6 wherein X is chlorine.
 8. A composition as in claim 7 wherein tHe compound is 2,6-di-t-butyl-4-(trichlorovinylthio) phenol. 